As is known, a vacuum cleaner, an electric broom or a similar electric household appliance for performing cleaning by means of suction comprises a suction head for sucking up dust, dirt or fluids from a surface. In the sector of electric household appliances, a suction head is generally referred to by the term “brush”. For the purpose of the present description, therefore, the terms “suction head” and “brush” are considered to be equivalent. Again for the purpose of the present invention, the term “vacuum cleaner” will be used with a broad meaning so as to include all those apparatus, for professional or domestic use, which perform cleaning by means of suction. Therefore, the term “vacuum cleaner” will comprise a vacuum cleaner, an electric broom, a so-called multi-purpose drum vacuum cleaner, a centralized suction system for domestic or industrial use and an apparatus for supplying and sucking in steam.
Basically a known suction head comprises a base plate shaped so as to have at least one base plate channel open towards a surface to be vacuumed, a suction channel which, during use, is joined to the base plate and is in fluid communication with the base plate channel and optionally a covering body which can be connected to the base plate/suction channel assembly. The other end of the suction channel communicates with a suction tube usually via a rotatable joint. Also known are suction heads in which the suction channel, during use, is joined to the covering body.
In order to avoid an incorrect interpretation of certain expressions which will be frequently used during the course of the present description and in the claims, a number of definitions are provided hereinbelow:                the expression “width” of a suction head, will be understood as meaning the maximum dimension (or footprint) of a suction head without the covering body and calculated substantially parallel to a longitudinal axis (or main longitudinal axis) of the base plate channel;        the expression “suction efficiency” will be understood as meaning essentially the ratio, in percentage terms, of the vacuumed material to the material to be vacuumed; The vacuuming tests are carried out in accordance with the provisions of the standard EN 60312-1:2013-05.        
GB 2 496 663 A discloses a cleaner head for a vacuum cleaner.
WO 2005/096907 A1 discloses a surface cleaning apparatus.
US 2014/033473 A1 discloses a floor tool for a vacuum cleaning apparatus.
GB 2 471 918 A discloses a surface treating head.
Although different suction heads which perform the function of sucking dust and/or fluids and/or dirt from a surface in a sufficiently efficient manner are available on the market, the Applicant has noticed that there exists the need to improve the performance of the known suction heads. In particular, the Applicant has noticed the need to increase the suction efficiency on carpets, rugs, doormats, matting or the like as well as on hard and substantially smooth surfaces such as floors consisting of marble, cement, resin, tiles, parquet or the like.
For many years, manufacturers have improved the performance of vacuum cleaners by increasing the power of the motors, without bothering about the associated increase in power consumption. By means of a high vacuuming power it has been possible to achieve an optimum vacuuming performance also without optimizing the various components of a vacuum cleaner brush.
At present, the existing standards which have been issued with the aim of reducing the power consumption, also in the sector of electric household appliances, have resulted in a substantial reduction in the power of electric household appliances and the need to optimize the components in order to ensure performance levels comparable to those of the preceding models.